Steering lock for a motor vehicle

ABSTRACT

The invention relates to a motorized steering column lock for a motor vehicle, comprising a bolt ( 30 ) that is able to move between a column locking position and a column unlocking position, and also an electric motor ( 10 ) for driving the bolt between the unlocking position and the locking position, characterized in that the bolt is mounted so as to approach the steering column in a direction parallel to the steering column.

The invention relates to steering-column locks of the electricallymotorized type.

Many constructions of steering-column locks are known. First,steering-column locks have been proposed comprising a motor and agearwheel which drives a locking bolt via a cam or a gradient associatedwith the gearwheel, wherein the gearwheel rotates about a shaft which isparallel to the output shaft of the electric motor, or else in which thegearwheel rotates about a shaft which is perpendicular to the outputshaft of the electric motor.

The bolt then travels in a sliding manner closer to the steering columnunder the action of a cam or of a gradient formed by the gearwheel untilit engages a peripheral ring gear of the steering column.

The known electrically motorized steering-column locks also have toogreat a space requirement for a certain arrangements with considerablespace constraints, such as arrangements in a bottom portion of thesteering column, for example close to or incorporated into a motorizedassistance module for assisting the rotation of the steering column.

The object of the invention is to alleviate the drawbacks of the knownelectrically motorized steering locks and notably to propose asteering-column lock configuration that can be housed in a restrictedspace in the bottom portion of the steering column.

This object is achieved according to the invention by virtue of amotorized steering-column lock for a motor vehicle comprising a boltthat can move between a locked position and an unlocked position of thecolumn and an electric motor for driving the bolt between the unlockedposition and the locked position, characterized in that the bolt ismounted so as to approach the steering column in a direction parallel tothe steering column.

Other features, objects and advantages of the invention will becomeapparent on reading the following detailed description made withreference to the appended figures in which:

FIG. 1 is an overview of a steering lock according to a preferredembodiment of the invention;

FIG. 2 is an exploded view in perspective from above of this samesteering lock;

FIG. 3 is an exploded view in perspective from below of this samesteering lock;

FIG. 4 is a partial view of this same steering lock in the unlocked andimmobilized position of this same steering lock;

FIG. 5 the position is a partial view of this same steering lock in thelocked and released position of this same steering lock;

FIG. 6 is a partial view with no shuttle and from below of this samesteering lock in the unlocked and immobilized position;

FIG. 7 is a partial view with no shuttle and from below of this samesteering lock in the locked and released position;

FIG. 8 is a partial view with no shuttle and from above of this samesteering lock in the unlocked position;

FIG. 9 represents an assembly consisting of a steering column and amodule for assisting the pivoting of a steering column which moduleincludes a steering lock according to one embodiment of the invention.

The steering lock shown in FIG. 1 comprises an electric motor 10furnished with an output shaft forming a worm 15, a gearwheel 20 engagedin the worm 15, a bolt 13 mounted so as to slide, these various elementsbeing placed in a housing 40.

The gearwheel 20 is mounted so as to rotate about a shaft 21 whichextends perpendicularly to the output shaft of the motor 10 so that theoutput shaft of the motor is indistinguishable in the geometric plane ofthe gearwheel.

The gearwheel 20 has a first face 22, turned toward a steering columnnot shown, which is furnished with a cam 23 in a disk portion whichinteracts in thrust with the bolt. For this purpose, the bolt 30 has, inaddition to a main bar 31, a lateral appendage 35 capable of beinginterposed on the path of the cam 23 when the latter pivots with thegearwheel 20 in order to come closer to an outer ring gear of thesteering column. The bolt is advantageously returned to the lockedposition by a spring.

This lateral appendage has the shape of an S of which the top curveforms a bearing wall for the cam 23 of the gearwheel and of which thebottom curve receives within it an element for retention in the unlockedposition as will be described below.

Therefore, when the gearwheel 20 is rotated, the bolt 30 travelsslidingly in a plane parallel to the main plane of the gearwheel. Sincethe gearwheel 20 is in this instance oriented such that it is in a planeparallel to the steering column, the bolt therefore itself travelsparallel to the main direction of the steering column.

In order to be locked when the bolt is in the final position, thesteering column has a lateral appendage interacting with the bolt, inthis instance a ring gear 80 of which the teeth have between theminterstices accommodating the bolt in its extended locked position.

In another embodiment, the lateral appendage may be a simple finger ofradial orientation relative to the main direction of the steeringcolumn, or else a transverse plate furnished with a series ofthrough-holes and capable of accommodating the bolt in multiple angularpositions of the steering column.

The gearwheel 20 has, on its face oriented away from the column, a trackin an arc of a circle 24 formed here in the form of a built-up elementout of the face of the gearwheel 20.

The track 24 extends over three-quarters of the angular extent about theshaft of the gearwheel 20 and has, at each of its ends, a sliding bevelwhich adjoins the main plane of the face 22.

The track 24 interacts with a shuttle 60 mounted so as to move slidinglysideways to the main plane of the gearwheel and more specifically inthis instance mounted so as to slide on the rotation shaft of thegearwheel.

This shuttle has a radial extension 62 in the direction of the bolt 30and, via a finger 64 oriented sideways to the main plane of thegearwheel 20, extends inside the bolt 30 in a selective manner as willbe explained below.

Specifically, the shuttle 60 rests against the track 22 via a slide 65formed in relief on the shuttle face turned toward the gearwheel and theshuttle is thus kept resting against the track 24 sideways to thegearwheel 20 by a spring, not shown. Due to this, the shuttle sustains amovement sideways to the gearwheel while the latter pivots on itselfwhen the slide 65 rises or falls from the built-up track 24. During thismovement, the shuttle 60 is held against a pivoting about the rotationshaft of the gearwheel by interaction of a finger, not shown, made ofthe same material as the steering-lock housing and engaged in an orificepassing through the shuttle 60.

As shown in FIG. 8, the built-up track 24 is placed such that, when thebolt is in the locked position of the steering column, the shuttle isseparated from the gearwheel, that is to say that the slide 65 isresting on the track 24 and the overlocking finger of the shuttle doesnot then engage the bolt. Conversely, the built-up track is placed suchthat the shuttle 60 is brought closer to the gearwheel, that is to saythat the slide 65 is out of the track 24 when the bolt is in theunlocked position and that the shuttle then secures, by the overlockingfinger, the bolt in the unlocked position. Accordingly, the S shapeformed by the bolt has its proximal curve to the main body of the boltfacing the overlocking finger when the bolt is in the unlocked position,thus allowing the overlocking finger to penetrate the proximal curve ofthe S. The finger is then positioned as an obstacle on the return pathof the bolt and more specifically of the proximal curve of the S, thuspreventing an inadvertent return of the bolt to its locked position.

As an alternative, the built-up element presented by the track 24increases during the travel of the track such that a first end of thearc of a circle described by the track is close to a main plane of thegearwheel and another end of the arc of a circle described by the track24 is further away sideways from the main plane of the gearwheel 20.

By virtue of the present orientation of the bolt moving parallel to thesteering column, whether it be driven by a gearwheel thus positioned orpositioned differently for example perpendicularly to the steeringcolumn, it gives an overall space requirement of the steering-columnlock that is particularly low and notably in the direction radial to thesteering column.

This low space requirement is particularly notable in the case in whichthe gearwheel is oriented parallel to the steering column, but a gain inspace requirement is already easily obtained by such an orientation ofthe movement of the bolt even when the gearwheel is perpendicular to thesteering column.

Moreover, although a bolt sliding parallel to the steering column ispreferred in terms of space requirement, a gain in space requirement isalready obtained when the portion of the bolt that engages the steeringcolumn approaches the steering column in a direction substantiallyparallel to the column, whether the bolt slides or rotates, in whichcase a movement of the substantially tangential end of the bolttherefore parallel with the column or a lateral appendage of the latterprovides a considerable advantage in terms of space requirement of thesteering lock.

In the present example, the housing 50 of the steering lock isadvantageously arranged in the form of a liquor bowl, that is to say asan extension in the main direction of the steering column and in a crosssection in the shape of a bean, that is to say included between twotransverse limits in an arc of a circle of respectively lesser andgreater radius.

The steering-column lock then closely follows a cylinder contour of thesteering column so as to occupy only a small space radial to the column.Such a space requirement is particularly advantageous in the presentcase in which the steering-column lock is an element constituting amodule of motorized assistance to the rotation of the steering column.Incorporating the steering lock in a module of motorized assistance tothe pivoting of the steering column provides an advantage in terms ofsafety since the steering lock is then in a particularly low portion ofthe column, at a particularly great distance from the instrument panelwhere it is the predilection of a thief to operate and in a particularlyinaccessible portion of the vehicle.

In the present case and as shown in FIG. 9, the motorized assistancemodule comprises an assisting motor 70 which is oriented such that itsoutput shaft 75 extends parallel to the steering column. The outputshaft 75 of the motor 70 has peripheral gear teeth in which a ring gear80 surrounding the steering column meshes in order to rotate the latter.The ring gear 80 is advantageously the ring gear in which the bolt 30engages such that only one ring gear is used for the two functions ofdriving and immobilization, further reducing the space requirement forthe implementation of the described assisting module.

Advantageously, the steering lock and the assisting motor 70 are placedradially opposite to the steering column such that the bolt 30 and theoutput shaft of the assisting motor do not interfere. The motorizedassistance module advantageously comprises one and the same electronicunit for controlling the pivoting assistance and controlling theimmobilization of the column, which ensures that no assistance controlis applied to the assisting motor when the steering lock is in thelocked position.

Because the steering-column lock is a portion of the module formotorized assistance of the rotation of the steering column, the controlunit that is common to the motorized assistance and to the locking ofthe column is advantageously fitted with a control logic using a slightrotational movement of the steering column when it simultaneouslycommands a force to operate the unlocking of the bolt. Thus, by thisslight movement, any frictional retention is removed between the boltand the steering column, for example between the bolt and a lateral edgeof a tooth of the ring gear 80 and the bolt travels slidingly in areliable manner with each switching on of the vehicle.

The control unit is advantageously implemented in the form of anelectronic circuit placed in a common housing 90 of the assisting motor70 and of the steering lock. The electronic circuit is advantageouslypositioned outside the housing 50 of the steering lock. In addition tothe implementation of controlling the steering lock via this controlunit, in this instance notably takes account of the positioning of thebolt that is indicated to it by the receipt of output signals fromsensors of positioning of the bolt that are placed in the steering lock.These two sensors, referenced 35 and 36, are in this instance magneticsensors activated by a magnet placed on the bolt but which, as avariant, can be mechanical sensors activated by a boss of the bolt. Asan alternative, they may be sensors associated with the gearwheel, theimmobilizing shuttle or any other member of the steering lock. Thesignals delivered by these sensors are advantageously directly read bythe control unit.

1. A motorized steering-column lock for a motor vehicle comprising: a bolt configured to move between a locked position and an unlocked position of the column; and an electric motor for driving the bolt between the unlocked position and the locked position, wherein the bolt is mounted so as to approach the steering column in a direction parallel to the steering column.
 2. The steering-column lock as claimed in claim 1, wherein the electric motor has an output shaft and a worm placed on the output shaft and a gearwheel in which the worm of the motor output shaft is engaged, the gearwheel being oriented in a plane parallel to the steering column.
 3. The steering-column lock as claimed in claim 1, wherein the motor is oriented so that its output shaft is in a plane parallel to the steering column.
 4. The steering-column lock as claimed in claim 1, wherein the bolt is mounted so as to slide in the steering lock in a sliding direction parallel to the steering column.
 5. The steering-column lock as claimed in claim 1, further comprising an element that can move between a position of immobilizing the bolt in the unlocked position and a position of releasing the bolt.
 6. The steering-column lock as claimed in claim 5, wherein the electric motor has an output shaft and a worm placed on the output shaft and a gearwheel in which the worm of the output shaft of the motor is engaged and the movable element for immobilizing the bolt is resting on a portion of the gearwheel which pushes the movable immobilizing element away from the bolt when the gearwheel is rotated.
 7. The steering-column lock as claimed in claim 6, wherein the gearwheel has a track in an arc of a circle progressively moving away laterally from the gearwheel and the movable immobilizing element is resting against the track so as to move closer and further away when the gearwheel is rotated.
 8. A module for assisting the rotation of a steering column comprising an assisting motor applying a pivoting force to the steering column, wherein the module comprises a steering lock as claimed in claim
 1. 9. An assembly comprising a steering column of a motor vehicle and a steering lock as claimed in claim
 1. 10. A combined assembly of a steering column of a motor vehicle and a module for assisting the rotation of the steering column as claimed in claim 8, wherein the steering column comprises a peripheral ring gear in which the bolt is engaged in the locked position and which peripheral ring gear receives a steering-column pivoting force delivered by the assisting motor. 